Predicting Atherosclerosis Disease in Patients With Diabetes

Carotid ultrasound shows atherosclerotic disease is not just a concern for patients with type 1 and type 2 diabetes, but LADA as well.

Approximately 4-14% of patients originally diagnosed with type 2 diabetes are reclassified as having latent autoimmune diabetes of adults (LADA). It is well known that macrovascular disease is the leading cause of morbidity and mortality in patients with type 1 and type 2 diabetes. However, little is known about the cardiovascular risks associated with patients diagnosed with LADA. Early diagnosis and treatment of carotid atherosclerosis greatly reduces a patient’s chances of experiencing a cardiovascular event. Although controversy surrounding the use of carotid ultrasound in the detection of preclinical atherosclerosis remains, it still proves to be a safe, non-invasive, and efficient way to evaluate the narrowing of the carotid arteries.

A recent cross-sectional analysis, published in Cardiovascular Diabetology, evaluated carotid atherosclerotic disease in patients with type 1 diabetes, type 2 diabetes, and LADA. Researchers recruited 116 with type 1 diabetes, 191 patients with type 2 diabetes, and 71 patients with LADA. The study cohorts were similar in gender distribution, age, smoking status, HbA1c, and the use of antihypertensive medications. All study participants had a urine albumin-to-creatinine ratio less than 300 mg/dg and an estimated glomerular filtration rate greater than 60mL/min/1.732. Although patients were matched according to age, the duration of diabetes varied amongst the three groups. Patients with type 1 diabetes had the longest duration of disease followed by patients with LADA and then patients with type 2 diabetes.

Conditions such as diabetic retinopathy was expected to be more prevalent in patients with a longer duration of a diagnosis of diabetes and was most common in patients with type 1 diabetes. Furthermore, the absence of clinical cardiovascular disease and diabetic neuropathy was required as part of the inclusion criteria. It is important to note that patients with type 2 diabetes exhibited more adverse lipid profiles and anthropometric measures in comparison to patients with type 1 diabetes or patients with LADA. Patients with type 2 diabetes were also less likely to be on a statin regimen in comparison to the other two cohorts.

Carotid ultrasound sonography was conducted by two non-blinded imaging specialists using a high-resolution ultrasound machine. Plaques were identified and the intima-media-adventitia thickness (IMT) measured using B-mode and color Doppler. Subclinical carotid atherosclerosis was defined by the presence of one plaque in any portion of the carotid artery and more severe carotid atherosclerosis was defined by the presence of multiple plaques.

Researchers concluded that patients with type 1 diabetes demonstrated lower carotid IMTs in comparison to patients with type 2 diabetes or LADA. However, 73.2% of patients with LADA showed the presence of atherosclerotic plaques in comparison to patients with type 1 diabetes (57.1%, p-value: 0.026) and patients with type 2 diabetes (56.9%, p-value: 0.019). Patients with LADA were also more likely to have more severe atherosclerotic disease as evidenced by numerous plaques along the carotid arteries in comparison to patients with type 1 or type 2 diabetes. These findings were surprising to researchers, as it was assumed that the prevalence of plaque formation and severity of atherosclerotic disease would be greater in patients with type 2 diabetes, especially because patients with type 2 diabetes were less likely to be on a statin regimen. The high incidence of carotid plaque formation in patients with LADA remained despite researchers adjusting for cardiovascular risk factors, such as diabetes duration.

Current guidelines recommend against the use of carotid ultrasound sonography as a tool to predict an individual patient’s risk for a cardiovascular event. However, it is known that the presence of carotid plaques serves as a good predictor of a patient’s risk for future cardiovascular events. The results of this study indicate that the frequency of carotid atherosclerosis is not selective for patients with type 1 or type 2 diabetes, but that patients with LADA have comparable if not greater incidences of atherosclerotic disease. These findings draw attention to the importance of screening for atherosclerotic disease across all types of diabetes.

Practice Pearls:

Early carotid plaque detection may help focus on more preventative strategies for patients with diabetes.

Up to 14% of patients with LADA are misdiagnosed with type 2 diabetes.

Patients with LADA may be at a higher risk of cardiovascular events in comparison to patients with type 1 or type 2 diabetes.